Seven day programmable hot water controller

ABSTRACT

The multi-day programmable hot water heater controller employs a control circuit, in communication with a temperature sensor and a switching device, to control the operation of a water heater. The temperature sensor is attached to a water heater, positioned where the water temperature within the water heater can best be read. Temperature loss between the water and the temperature sensor may be determined by calculation or measurement, and corrected by the control circuit. The multi-day programmable hot water heater controller monitors water temperature within the water heater, and controls the switching device to switch the water heater on or off, maintaining the water temperature according to programmable parameters. Users program the multi-day programmable hot water heater controller to define periods during which the water heater is operated to maintain a desired water temperature. At other times, the water heater is turned off to conserve energy.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/643,122, filed Jan. 12, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to water heating appliances and, more particularly to a multi-day programmable hot water heater controller.

2. Description of the Related Art

Certain home or commercial appliances, or other equipment, operate continuously, or cyclically, over long periods of time to maintain environmental or other conditions within a comfortable range. Residential heating systems, for example, operate in a continuous on/off cycle to maintain a living space at a comfortable temperature. Similarly, hot water heaters typically operate in a similar continuous on/off cycle to maintain a water supply at a desirable temperature for use.

Such systems generally experience periods of high use or demand, and periods of low demand. For example, in a residential setting, hot water usage is often highest during a morning period where family members shower, prepare and clean up after a morning meal, and perform other tasks utilizing hot water. Hot water may go entirely unused during midday hours, until evening activities such as dinner preparation and cleanup lead to increased hot water usage.

Concerns with conservation, or reduction in the costs associated with operating a hot water heater, have led to various systems intended to reduce energy expenditure and costs by matching production and maintenance of a hot water supply to such periods of high and low demand. Programmable control devices have been proposed to allow thermostatic control of a hot water heater to maintain various temperature settings during different periods of the day. Such systems tend to be ill suited for retrofit to existing hot water heaters, or require the entire replacement of a thermostatic control in the existing hot water heater. Further, some such systems employ a plurality of discrete thermostatic devices to effect different temperature settings for different periods of the day (for example, a first thermostat to set a low temperature, a second thermostat to set an intermediate temperature, and a third thermostat to set a high temperature).

Thus a multi-day programmable hot water heater controller solving the aforementioned problems is desired.

SUMMARY OF THE INVENTION

The multi-day programmable hot water heater controller employs a control circuit, in communication with a temperature sensor and a switching device to control the operation of a hot water heater by controlling a power supply to the hot water heater (or a gas supply, in the case of some gas heaters), the control circuit controlling the switching device to switch the power supply to the hot water heater on and off.

A temperature sensor is attached to a hot water heater, in a position where the water temperature within the hot water heater can best be read, such as on a hot water outlet pipe leading from the hot water heater. Any temperature loss between the pipe's direct contact with the hot water and the placement of the temperature sensor may be determined by calculation or measurement, and an appropriate correction or compensation may be made by the control circuit.

In its most basic operation, the multi-day programmable hot water heater controller monitors the water temperature within the hot water heater using the temperature sensor, and controls the switching device to switch the hot water heater on or off as required to maintain the water temperature according to programmable parameters. Users program the multi-day programmable hot water heater controller to define operational time periods during which the hot water heater is operated to maintain a desired water temperature. At other times, the hot water heater is turned off to conserve energy.

These and other features of the present invention will become readily apparent upon further review of the following specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is system block diagram of a multi-day programmable hot water heater controller according to the present invention.

FIG. 2 is a block diagram of a controller for a multi-day programmable hot water heater controller according to the present invention.

FIG. 3 is a flowchart describing a general operation of a multi-day programmable hot water heater controller according to the present invention.

Similar reference characters denote corresponding features consistently throughout the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is a multi-day programmable hot water heater controller, designated generally as 10 in the drawings. Referring to FIG. 1, the multi-day programmable hot water heater controller 10 controls the operation of a hot water heater 90 by controlling a power supply to the hot water heater (or a gas supply, in the case of gas heaters).

In the embodiment illustrated in FIG. 1, a conventional electric hot water heater 90 is shown having a thermostat 94 controlling an electric heating element 92 within the hot water heater 90. The multi-day programmable hot water heater controller 10 includes a relay 24 that, under the control of the multi-day programmable hot water heater controller 10, switches the power supply to the thermostat 94 on and off.

A temperature sensor 26 is attached to the hot water heater 90, positioned on the hot water heater 90, or on a water pipe extending from the hot water heater 90, in a position where the water temperature within the hot water heater 90 can best be determined. For example, a hot water outlet pipe leading from the hot water heater 90 may provide a useful measurement point, since the hot water outlet pipe is in direct contact with the hot water within the hot water heater 90. Any temperature loss between the pipe's direct contact with the hot water and the placement of the temperature sensor may be determined by calculation or measurement, and an appropriate correction or compensation may be made by the multi-day programmable hot water heater controller 10.

In its most basic operation, the multi-day programmable hot water heater controller 10 monitors the water temperature within the hot water heater 90 using the temperature sensor 26, and controls the relay 24 to switch the hot water heater 90 on or off as required to maintain the water temperature according to parameters set within the multi-day programmable hot water heater controller 10. It can be understood that the thermostat 94 of the hot water heater 90 will be set somewhat higher than the maximum temperature that will be programmed into the multi-day programmable hot water heater controller 10, giving the multi-day programmable hot water heater controller 10 full control of the water temperature. It should be noted that the relay 24 is illustrated for the control of hot water heating systems that employ a 120, or 240 volt power supply for operation (typically electric, oil fired, and some gas systems). The relay 24 may be replaced with an electric solenoid valve or another control in certain embodiments such as a gas hot water heater, or eliminated entirely for systems using a relatively low voltage control signal.

Referring now to FIGS. 1 and 2, the multi-day programmable hot water heater controller 10 comprises a control circuit 28, in communication with a display 12, a status lamp 14, such as a Light Emitting Diode (LED), and a plurality of pushbuttons 16, 18, 20, 22. In the illustrated embodiment, the multi-day programmable hot water heater controller 10 uses a pair of scroll buttons 16 to allow setting of time, temperatures, selection of days, and other user functions. An override button 18 allows a user to, at the touch of a button, override the programmed functions of the multi-day programmable hot water heater controller 10 such as for a vacation period. A set button 20, and a mode button 22, allow further user interactions with the multi-day programmable hot water heater controller 10 as will be described below.

The display 12 includes alphanumeric display components suitable for displaying dates, time of day, temperatures, and so forth. Additionally, the display 12 includes display components for indicating days of the week, to allow user selection of a day of the week for programming purposes. The display may be illuminated, either by employing a light emitting display such as an LED or electro-luminescent or similar technology, or by providing a backlight or perimeter lighting or other light source for illuminating the display surface for viewing.

In the illustrated embodiment, the control circuit 28 is a typical microprocessor-based circuit including a CPU 30 and memory 34, the memory including both areas of RAM and ROM, to contain a computer program for execution by the CPU 30. Additionally, the control circuit 28 employs a timer 32.

The control circuit 28 is in communication with the temperature sensor 26, receiving a signal indicating the temperature measured by the temperature sensor 26. Additionally, the control circuit 28 is in communication with the relay 24, the control circuit 28 providing a signal to open and close the relay 24.

Turning now to FIG. 3, the operation of the multi-day programmable hot water heater controller 10 is discussed in greater detail. In the illustrated embodiment, the operation of the multi-day programmable hot water heater controller 10 is directed by a computer program stored in the memory 34 and executed by the CPU 30.

In a basic operational mode (step 302), the control circuit 28 performs basic tasks such as time keeping or clock functions, and operates the hot water heater 90 according to programmed temperature a n d time settings. The programmed temperature and time settings specify one or more operational time periods within a day, each operational time period being defined by a start and a stop time. Non-operational time periods are the time periods during a day falling outside of any operational time period.

During an operational time period, the control circuit 28 reads the temperature sensor 26, and issues a control signal to cause the relay 24 to apply power to the hot water heater 90 when the temperature sensor 26 indicates a water temperature below the temperature setting programmed for the operational period. If the temperature sensor 26 indicates a water temperature at or above the temperature setting programmed for the operational period, the control circuit 28 causes the relay 24 to remove power from the hot water heater 90. Thus, during operational time periods the control circuit 28 monitors the water temperature and operates the hot water heater 90 cyclically to maintain the programmed water temperature for the operational time period. During the operational time period, the lamp 14 may be continuously illuminated to indicate the operational time period, or the lamp may be illuminated only when the hot water heater 90 is powered.

During non-operational time periods, the control circuit 28 controls the relay 24 to keep power removed from the hot water heater 90 until another operational time period.

Additionally, during the multi-day programmable hot water heater controller 10 monitors the pushbuttons 16, 18, 20, and 22 for user inputs (step 304). When the multi-day programmable hot water heater controller 10 is in the basic operational mode, only the override button 18 and the mode button 22 will be recognized. If the override button 18 is depressed, the multi-day programmable hot water heater controller 10 enters an override mode (step 306). The override mode may be a vacation or similar mode wherein the control circuit 28 suspends the ordinary programmed operating schedule, and controls the relay 24 to keep power removed from the hot water heater 90 until the override mode is exited. Exit from the override mode may occur following a programmable time interval, at a programmable date and time or by pressing the override button 18 when the controller is in the override mode. On exit from the override mode, the control circuit 28 returns to the basic operational mode (step 302).

Depressing the mode button 22 in the basic operational mode causes the control circuit 28 to enter a programming mode (step 308), allowing the user to set the clock time, or to set the start and stop times, and temperature for operating periods. The user may depress the mode button 22, or otherwise step through programming choices to perform the different programming tasks. On entry into a set time programming mode (step 310) the user may set the correct time of day and date, using the scroll buttons 16 to change hour or minute settings, and pressing the set button 20 to enter a new time and date.

Proceeding to program an operational time period, the user first selects a day (step 312), using the scroll buttons 16. The user may create operational time periods for each day of a week individually, or may enter settings categorically for weekdays and weekends. For example, rather than enter operational time periods for each of Monday, Tuesday, Wednesday, Thursday, and Friday, the user may simply specify a “weekday” programming.

Following selection of a day, the user may enter one or more operational time periods, first defining the start and stop times for an operational time period (step 314), and then specifying the water temperature during the operational time period. As with setting the time and day, the scroll buttons 16 are used to increment or decrement the time and temperature, and the set button 20 is used to enter each data item. Once the user has entered an operational time period, the user may elect to enter an additional operational time period or return to the basic operational mode.

It is to be understood that the present invention is not limited to the embodiment described above, but encompasses any and all embodiments within the scope of the following claims. 

1. A multi-day programmable hot water heater controller, comprising: a temperature sensor; a display device; a plurality of input pushbuttons; a microcomputer based control circuit in electrical connection with said temperature sensor, display device, and pushbuttons; means for operating a hot water heater under the control of said control circuit; and a computer readable program code contained in said microcomputer based control circuit, said program code having means for determining the temperature of water contained within said hot water heater from a signal read from said temperature sensor, means for entering a start time, a stop time, and a desired temperature for at least one operational time period, and means for maintaining the temperature of water within said hot water heater at said desired temperature during said operational time period.
 2. The multi-day programmable hot water heater controller of claim 1, wherein said means for operating a hot water heater under control of said control circuit further comprises: a relay operably connected between said control circuit and a thermostat of a hot water heater said relay configured to control said thermostat based on relay control signals received from said control circuit.
 3. The multi-day programmable hot water heater controller of claim 2, wherein said relay comprises an electric solenoid valve.
 4. The multi-day programmable hot water heater controller of claim 1, further comprising a status lamp in electrical connection with said control circuit.
 5. The multi-day programmable hot water heater controller of claim 1, wherein one of said plurality of buttons comprises an override button in electrical connection with said control circuit, said override button selectable by a user to override any programmed functions of the control circuit.
 6. The multi-day programmable hot water heater controller of claim 1, wherein said control circuit further comprises a timer for controlling based on the time of day and the day of the week.
 7. The multi-day programmable hot water heater controller of claim 1, wherein said at least one operational time period is defined by a programmed start and stop time.
 8. A method for controlling a multi-day programmable hot water heater controller comprising a temperature sensor, a display device, a plurality of input pushbuttons, a microcomputer based control circuit in electrical connection with said temperature sensor, display device, and pushbuttons, means for operating a hot water heater under control of said control circuit, and a computer readable program code contained in said microcomputer based control circuit, said method comprising the steps of: determining the temperature of water contained within a hot water heater from a signal read from said temperature sensor; entering a start time and a stop time defining an operational time period; entering a desired temperature for said operational time period; and maintaining the temperature of water at said desired temperature during said operational time period.
 9. The method for controlling a multi-day programmable hot water heater controller of claim 8, wherein said step of maintaining the temperature of water at said desired temperature during said operational time period further comprises the steps of: reading a temperature signal from said temperature sensor; determining if said temperature signal is below said desired temperature; issuing a first control signal to a relay to apply a heat source to a hot water heater based on said step of determining if said temperature signal is below said desired temperature; reading a temperature signal from said temperature sensor after said step of issuing a control signal; determining if said temperature signal is at or above said desired temperature; and issuing a second control signal to said relay to turn off said heat source to a hot water heater based on said step of determining if said temperature signal is at or above said desired temperature.
 10. The method for controlling a multi-day programmable hot water heater controller of claim 9, further comprising the step selected from the group consisting of: illuminating a lamp on said controller during said operational time period; and illuminating a lamp on said controller during said step of issuing said first control signal to said relay to apply a heat source to a hot water heater.
 11. The method for controlling a multi-day programmable hot water heater controller of claim 9, further comprises the steps of: receiving an override command from an override input pushbutton; suspending a programmed operating schedule in said control circuit based on said step of receiving an override command; resuming said programmed operating schedule in said control circuit, selected from the group consisting of: at a programmable time interval; at a programmable date and time; and by receiving a second override command from said override input pushbutton.
 12. The method for controlling a multi-day programmable hot water heater controller of claim 8, wherein said step of entering a start time and a stop time defining an operational time period further comprising the step of: selecting a day of the week with said input pushbuttons.
 13. The method for controlling a multi-day programmable hot water heater controller of claim 12, further comprising the step of: entering a second start time and a second stop time defining a second operational time period. 